The present invention relates to a semiconductor device, a power amplifier device, and a personal computer (PC) card and, for example, to a technique effectively applied to manufacturing of a PC card for a wireless LAN.
As penetration of personal computers to offices and homes increases, communication between personal computers typified by the Internet is being actively performed. Attention is being paid to a wireless LAN (local area network) for performing the communication between personal computers wirelessly, not by wire. At present, a wireless LAN conformed to the 2.4-GHz band “IEEE (The Institute of Electrical and Electronics Engineers, Inc.) 802.11b” standard is in the mainstream. However, since the transmission speed is 8 Mbps at the maximum and is low, it causes a problem that a moving image cannot be transmitted. One of solutions to the problem is a wireless LAN of the 5 GHz band “IEEE802.11a” standard enabling the maximum transmission speed of 54 Mbps.
In a PC card for use in the wireless LAN, an antenna, a transmission/reception change-over switch, a low-noise amplifier for reception, a mixer for reception, a mixer for transmission, a power amplifier for transmission, and the like are assembled.
Semiconductor devices of high frequencies such as a few GHz (for example, an HEMT (High Electron Mobility Transistor), an MMIC (Monolithic Microwave IC), and the like) are formed on the basis of a compound semiconductor substrate such as a GaAs substrate.
On the other hand, in a field effect transistor (FET) to increase the performance of a device in a high frequency band, for example, in place of a configuration of connecting a source electrode on the top face of a semiconductor chip and a source terminal of a package substrate via a wire, a via hole penetrating a semiconductor chip is provided, a conductor is formed in the via hole, the source electrode on the top face of the semiconductor chip is led to the under face of the semiconductor chip and, when the semiconductor chip is fixed to the package substrate, the led source electrode is directly connected to the source terminal of the package substrate (seating), thereby achieving reduction in the source inductance (refer to, for example, Patent Reference 1).
As a power amplifier for transmission (power amplifier device for transmission) in a mobile communication system, there is a module or an integrated circuit (MMIC) using a GaAs-MESFET or a hetero junction bipolar transistor (HBT) (for example, Patent Reference 2).
[Patent Reference 1]
Japanese Unexamined Patent Publication No. Hei 8 (1996)-330568, pp. 2-3, FIG. 1
[Patent Reference 2]
Japanese Unexamined Patent Publication No. Hei 11(1999)-220344, pp. 2-5, FIGS. 1 and 8